Air speed annunciator



July l1, R933, E ggg-{Bmwlggffi f'@ AIR SPEED ANNUNCIATOR Filed Mayr 9, 1952 5 Sheets-Sheet l O rdf" ,EZB

'n /Nl//VOQ JESSE E. 53h/5,4 UGH July 11, 1933. J. E. ESHBAUGH 1,917,959

AIR SPEED ANNUNCIATOR Filed May 9, 1932 3 Sheets-Sheet 3 /N//e/VTOQ Jesse E fsf/@HUGH @y ZM /L a A fron/Vey.;

Patented July 11', '1933 rellen JESSE E. ESHBAGH,

or frLmr, MICIGAN` AIR SPEED ANNUNGIATOR Application flied May 9,

This invention relates to an speed alinunciator for aircraft and the principal ob- ]ect of the same 1s to provide an apparatus for automatically notifying` the occupants of an airplane, by audible means, .of the upper and lower limits'of a predetermined speed range. l Y Another object of the invention is to pro vide an audible air speed annunciator elnbodying a shutter-controlled siren iu which the normal audible indication ot the V.siren is desroyed or modified over any desired speed range by shutting off the Vair supply essential to the operation of the siren.`

provide control of a siren'by means of dy.- namic air pressure created by relative motion between air and siren, the said all' pressure acting on a spring-controlled vaneV vice, partly broken away-to show an initial setting of the shutter for a predetermined speed range;

Figure 2 is a similar view showing the position of the shutter after a predetermined movement from its initial position fin Figure l.

Figure 3 is a View showing the initial setting` ot the shutter for a different speed range; Y 1

Figure 4 is a central .longitudinal sectional view of the device on an enlarged scale;

Fieure 5 is an enlarged plan of the shutter alsembly, and Y.

A further object of the inventn is toV Figure. 1 is a liront elevation of the demas. serial No. 610.259;

Figure 6 isa cross'section on line 6-6 of Figure. ,i

vThe device embodies acasing composed of alsiren shell 1 and a motor housing 2 connected by a tubularshatthousing. 3f The shell 1 isprovided Withaseries of circumferentially spaced, narrow, slots 4 anda cap or closure lcomprising spaced-apart members 5 and Shaving relatively aligned small central inlet openings or ports 7 and 8 Upon entering the siren shell through `the openings 7 and 8, the air `impinges a conically shaped detlector 9 centrally positioned behind the port 7 in the cap. and is thereby deflected through the peripheral openings orslots fi. The delfiector is a part of thel siren rotor 10 which also includes a plurality `of radial Vvenes 11 which, bytheir rapid iiiterruption of thel current of air passing through the shell while the rotor revolv` ing, produce the musical tones of the siren.

[The frequency of the interruptionsdeten motor housing 2 and electricallyconnected Cil through the conilnutator Mfbrushes 15, and

leads 16 and 17 to a battery V18. The bat-- tery .lead 16 includes the switch 19. t lwill be understood, however, that motor 13 may be replacedby any other source ot' power, such as an independent propeller, generator propeller, etc., Vwithout departing fromfthe spirit or" theinvention. y Y

It 1s a -well known'vfactthat a siren cannot :operate 1n a vacuunr/ ln putting` this invention into practice, itis intended Athatthe air supply to the rotor shall'be, substantially cut olf atv a certain predetermined `.speed which. will inturn result in' a marked differencein the intensity of tone generated by ythe siren. This is accomplished by means of a! shutter composed oi two superimposed leaves or segments 20 and 21 -pivoted mounted, as at 22, between the spaced apart cap-members 5 and 6 for movement aboutr a common axis. Each shutter segment is of' a; width slightly exceeding the-idiameter' of slrenport? in. lthecal) so that when the shutter is closed, that isn-when shutter segment 2l coincides with ythe shutter segment 20, the overall width of the shutter is just sufficient to enable the shutter, when disposed over the siren port 7 to Jfully cover the same and to substantially cut off the air supply to the rotor. By thus cutting off the.

upper end with an integral windfvane 23.

A spring 24 is connected at one end to the vane 23 and at the other end to thelow speed screw 25. Screw 25 is threadedly engaged in the bearing 26 of the low speed scale arm 27 mounted on the side of the siren shell 1.' The head of the screw has an index 28 for properly locating the screw relative to the graduation of the low speed scale 29. Adjustment of the low speed screw 25 varies the angular position of the shutter and either increases or decreases vthe, distance between the siren ports 7 and 8 and the leading edge A of shutter segment 20, accord.- ing to the direction of the screw-adjustment. Hence, the adjustment of the screw and the consequent positioning oi the shutter segment 2() relative to the siren ports 7 and 8 'determines the 4low air speed necessary to cause the shutter to cover the siren ports.

" The overall width of the shutter determines the highair speed necessary to move the shutter past the siren ports against the action of spring 24. The effective overall width of the shutter may be varied by the ysnreadinfr or o enin T of the shutter see`-` b C5 D ments 20 and 2l, the maximum overall width preferably being equal to the combined width of the respective shutters. The shutter segments are held to lany desired overall widths within given limits by a binding nut 30 on the outer end of a screw 31 carried by shutter segment 2O andworking in an arcuate slot 32 in shutter segment 2l. This latter segment is provided with a high speed scale 33 having a limited number of radial graduations or index lines 34 representing predetermined high 'speedwlimits-` Encircling the base of vane 23v ofshutter segment 20 is an adjustable high speed scale v 35 Vin the form of an endless ribbon, the graduations or index lines 36 of which correspond tothe radial indexes 34 of the high speed scale 33, being in effect merely vertical prolongations of the radial indexes. VThe adjustable ribbon ,scale is Vheld in any posi'- tion to which adjusted by means of a locl; screw 37. The shutter segment 20 is also provided, above the adjustable ribbon or high speed scale 35, with a fixed low'speed scale 38 corresponding to the low speed scale 29. Whenever an adjustment of the low speed screw 25 is made, the width of the shutter must obviously be varied if the same high speed limit is to be maintained. Scales 33 and 35 are used, as hereinafter explained, in conjunction with scale 38 in determining the properl adjustment oi2 the shutter segments whenever there is any change in the low speed setting of the shutter.

In the following description of the Voperation of' the device, it is assumed that the same Yis mounted ,on an airplane with the axis of rotor`l0 parallel to the line of flight with the vane 23 presented to the air stream at such an angle that the latter tends to move the vane, and hence the shutter, in a clockwise direction about its pivot 22 against the tension of spring v24. Theaxis of the rotor need not, necessarily, be parallel. to the v line of flight but in any event must be so 'is considered to bezil degree=2 miles per hour. In the Vposition of the parts, as illustrated in Figure 5, the shutter movements required to produce low and high speed warnings have Abeen designated by the letters X and YP Let it be assumed that the annunciator is to be set to operate at speed range having a low speed of 40 M.P.H. and' a high speed of 120 MPH. The low speed screw 25 is adjusted as shown in Fig. l until theindex 28 is opposite the graduation of the scale r29 corresponding to 40 miles per hour. This adjustment oi the screw positions shutter segment 2O with its Y leading edge A spaced from the farthest side of opening 7 a distance X corresponding to 2() degrees or 40 miles per hour, 1n accordance with the scale ofthe'apparatus. The

dynamic air pressure created by relativo mo- Vtion between air and siren, acting on the j spring-controlled'vane 23, moves the shutnecessary to again open the siren port by further deflection of the spring 24, thereby again making the siren normally operative. Since it is desired that the siren be normallyv operative at a high air speed of l2() miles per hour, the ribbon scale 3G is adj'usted on shutter segment 2O until its particulai'scale graduation or index-line desig-r vproperly adjusted,` the leading' edge of the' shutter segment 2l Will be adjacent tlie trailing' edge of shutter segment 20, as indicated at i3, so that tlie shutter is at itsmaxiinum Voverall Width, or a distance y correspondingr to elddegrees. This places the trailing' y edge et shutter segment 21 a distance Z, c(irresponding` to G0 degrees or l2() miles per honi', from the 'l'ai'tliest'siigle of siren port 7. Hencqtlie trailing` edge C ot the shutter will' not be moved past the opening 7 as shown in Fig'. 2 until the air speed increases 'troni 4l() to l2() miles per hour.

Should it be desired to reset the device for operationV at a diiiei'ent loiv speed limit While maintainingy tlie original high speed limit, it is necessary to make a corresponding' adjustment of the value Z For eX- ample, to change the low speed limit from Ll() miles `per hour to 50 miles per lioui',leav ing' the high speed limit at its original ligure i220, tlic'screiv 25 is first adjusted to the position corresponding to 5() miles per hour.

The resultant movement of the sliuttei' places tlie leading ledge A a distance FZ of 25 degrees, corresponding to 5U miles per liour, from tlie farthest side of' opening' 7 as shown in Fig'. The trailing` edge C, lioivever, will be a distance Z of 65 degrees, correspondingtto 130 miles per liour whereas only 'a higli speed limit et 120 miles per lioui' is desired. Hence, in oi'dei' that the high speed limit will remain at'lQO miles per liour, tlie distance Z must obviously be reduced. Thi. Width ot the slintter. A convenient vvay of doing 'his is to shift the ribbon scale 35 until allie scale niark 120 is aligned with the scale mark 50 ot' the loiv speed shutter scale 38. lflic shutter segment 2l is adjusted relative to the segment .20 and in a clockwise direc# tion until the radial scale mark 120 is properly lined up with thev pi'eviously aligned scale marks 120 and 50 of the scales 35 and 38, respectively. The distance e will tlien have a value of (i0 degrees or 120 miles per liour. For other speed ranges, tbe shutter segments shall be adjusted accordingly.

It will be observed that the foregoing is merely illustrative of a single embodiment oi' the invention and that in tlie practical application of tlie same, various changes, modification, and alterations in the scale and is accomplished by reducing' tlie overall` design of the annunciatormay be required to meet conditions ofuse. The invention is not to'be understood, therefore, as being limited to the exact construction herein setA Hforth but .rather susceptible to 'all such changes and modilications as fallv Within the limits and scope of the appended claims.

I claim: i

`vl. The combination with a siren of means responsive to dynamic air pressure created `by relative motion between air and 'siren :tor cutting off tlieair supply to the siren.

2. The combination with a shutter vconti'olled siren of shutter-.actuating m'sansresponsive to dynamic air pressure created by relative motion of air and siren for governn ing the position of the shutter.

3. The combination with a shutter-controlled siren of a spring-tensioned Wind vanek c the shutter and responsive to dynamic pressurecreated by relative motion olf air and siren for governing thepcsition 'of the shutter and hence the Lsound :produ-ced by the siren'.

" l. An air speed annuncijatoi' including a i Feo siren, means for causing cessationmof theA normal audible indication of the siren immediatelyy above a predetermined air speed., and means for restoring normal audible indication above a predetermined higher air speed.

5. An air speed aniiuii'ciator including' a Y' siren and inea-iis for shuttingfoil tlieptliuid supply essential to they operation {lf-the siren over a predetermined speed range, said means having,` a liigli and a lovv speed adjusti ment.

6. A device for indicating the upperfand loiver limits ol a predetermined speed lrange ,including asiren and means responsive to dynamic air prcssurei'or substantially cut ting off the air supply to tlieqsiren over the j iredetermined speed range to producefa marked difference in the intensity et tone generatedby the siren. f

. 7. A ldevice for indicating the upper and lower limits of a predetermined speed range including asiren and inieans `responsive to dynamic air pressure for cutting oil the air supply to the siren over the predetermined speed range, said means: liavingbotli a high spring.

wind vane Von said shutter responsive to air pressure tor moving the shutter against the action of the spring. Y l

l0. An air speed annunciator including a siren having an air-intake port, a shutter movable across said port for alternately closing and opening same, a tensionable connection between the shutter and the siren adjustable for varying theposition of the shutter laterally of the said air-intake port, and a wind vane on said shutter responsive to air pressure for moving the Ashutter against the tension of the spring.

1l. An air speed annunciator including a siren having an air-inlet, a shutter of variable width mounted` on said siren for movement across said air-inlet to alternately ciose and open the same, a tensionable connection between the shutter and the siren adjustable for varying the' position of the shutter laterally of the air-inlet, and a wind vane on said shutter responsive to air pressure tor moving the shutterl against the action of the l2. An air speed annunciator including a siren having an air-intake port, a multi-segmental shutter pivotally meunted on the siren and having the shutter segments relatively adjust-able for varying the overall width of the shutter, means on the shutter responsive to dynamic air pressure 'lier moving the shutter across the air-intake port to alternately cut off and restore the air supply essentialv to the operation ot the siren, adjustabie shutter-positioning means operable for properly positioning the shutter relative to the air-intake port soV that the air supply will be eut oli immediately abovethe lower limit 01' a predetermined air speed range, and means on said adjustable shutter segments correlated. with the shutter-positioning means for determining the width ot shutter required for the higher limit of the said predetermined speed range.

13. An air speed annnneiator including a siren shellihaving a series of circumferentially spaced air-exhaust slots, la closure for said shell comprising spaced inner and outer members having relatively aligned and centered air-inlet openings respectively7 a motor-driven siren rotor enclosed within said shell, a multi-segmental shutter pivotally mounted on the said closure between the inner and outer members thereof and having the shutter segments relatively adjustable for varying the overall width of the shutter a wind vane on one ot .the shutter segments responsive to dynamic air pressure for moving said shutter acrossV the said air-inlet openings to alternately cut off and restore the air supply essential to the operation lof the siren, a scale arm on said shell having a low speed scale, zin-adjusting screw threadedly engaged in said arm and having an index forproperly locating the screw relative to the graduations of the low speed scale, a spring connected at one end to the said screw and at the other end to the said vane, and scale means on the said adjustable shutter segments correlated with the low speed scale ot the said shell for determining the width ot' shutter required for any predetermined speed range.

lli. An audible air speed annunciator including a siren and means responsive to air pressure created by relative motion of air and siren for rendering` said siren inoperative between lower and'upper limits o'llv a given range. Y

l57 A speed indicator comprising the combination with a moving body of means earried thereby and responsive to relative motion between the body and the medium through which it moves for indicating by perceptible action the upper and lower lim- In testimony whereof I ailix my signature.

Y JESSE E. Esi-manon. 

